Added documentation about the verification of BalancingDispatcher + Router (added to both Dispatcher and Routing docs)

akka-docs/java/dispatchers.rst

@@ -85,6 +85,8 @@ There are 4 different types of message dispatchers:
                "thread-pool-executor" or the FQCN of
                an ``akka.dispatcher.ExecutorServiceConfigurator``
 
+  - Note that you can **not** use a ``BalancingDispatcher`` together with any kind of ``Router``, trying to do so will make your actor fail verification.
+
 * CallingThreadDispatcher
 
   - This dispatcher runs invocations on the current thread only. This dispatcher does not create any new threads,

akka-docs/java/routing.rst

@@ -375,7 +375,8 @@ The dispatcher for created children of the router will be taken from
 makes sense to configure the :class:`BalancingDispatcher` if the precise
 routing is not so important (i.e. no consistent hashing or round-robin is
 required); this enables newly created routees to pick up work immediately by
-stealing it from their siblings.
+stealing it from their siblings. Note that you can **not** use a ``BalancingDispatcher``
+together with any kind of ``Router``, trying to do so will make your actor fail verification.
 
 The “head” router, of course, cannot run on the same balancing dispatcher,
 because it does not process the same messages, hence this special actor does

akka-docs/scala/dispatchers.rst

@@ -86,6 +86,8 @@ There are 4 different types of message dispatchers:
                "thread-pool-executor" or the FQCN of
                an ``akka.dispatcher.ExecutorServiceConfigurator``
 
+  - Note that you can **not** use a ``BalancingDispatcher`` together with any kind of ``Router``, trying to do so will make your actor fail verification.
+
 * CallingThreadDispatcher
 
   - This dispatcher runs invocations on the current thread only. This dispatcher does not create any new threads,

akka-docs/scala/routing.rst

@@ -375,7 +375,9 @@ The dispatcher for created children of the router will be taken from
 makes sense to configure the :class:`BalancingDispatcher` if the precise
 routing is not so important (i.e. no consistent hashing or round-robin is
 required); this enables newly created routees to pick up work immediately by
-stealing it from their siblings.
+stealing it from their siblings. Note that you can **not** use a ``BalancingDispatcher``
+together with any kind of ``Router``, trying to do so will make your actor fail verification.
+
 
 .. note::